安卓工作室制作的导航抽屉:android.view.InflateException:膨胀类片段时出错

Question

我是android studio java的完全初学者，我遇到过这个错误，这个错误在这里似乎很常见。我看到了解决方案，但到目前为止没有任何帮助。在我的代码中，我使用安卓工作室已经制作的导航抽屉创建了一个导航抽屉。当我尝试运行应用程序时，我得到：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.covidmobileapp/com.example.covidmobileapp.MainActivity}: android.view.InflateException: Binary XML file line #15 in com.example.covidmobileapp:layout/activity_main: Binary XML file line #20 in com.example.covidmobileapp:layout/content_main: Error inflating class fragment

它似乎发现了我拥有的两个xml文件中的错误：activity_main.xml和content_main.xml

向下搜索堆栈跟踪，当创建应用程序视图时，似乎出现了错误

at com.example.covidmobileapp.MainActivity.onCreate(MainActivity.java:55)

这是我上面文件的代码：

主要活动.java

package com.example.covidmobileapp;
import android.os.Bundle;
import android.view.View;
import android.view.Menu;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.navigation.NavigationView;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.AppCompatActivity;

import com.example.covidmobileapp.databinding.ActivityMainBinding;
public class MainActivity extends AppCompatActivity {

private AppBarConfiguration mAppBarConfiguration;
private ActivityMainBinding binding;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
setSupportActionBar(binding.appBarMain.toolbar);
binding.appBarMain.fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = binding.drawerLayout;
NavigationView navigationView = binding.navView;
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
mAppBarConfiguration = new AppBarConfiguration.Builder(
R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow , R.id.nav_homepage)
.setDrawerLayout(drawer)
.build();
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
NavigationUI.setupWithNavController(navigationView, navController);
setContentView(R.layout.activity_main);

}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onSupportNavigateUp() {
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
return NavigationUI.navigateUp(navController, mAppBarConfiguration)
|| super.onSupportNavigateUp();
}


}

content_main.xml我已经评论了片段错误命中的行

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/app_bar_main">
<fragment
android:id="@+id/nav_host_fragment_content_main"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="@navigation/mobile_navigation" //this is where the fragment error hits 
/>
</androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml我也评论了错误在哪里

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
android:id="@+id/app_bar_main"
layout="@layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" /> //this is where error for activity_main is 
<com.google.android.material.navigation.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="@layout/nav_header_main"
app:menu="@menu/activity_main_drawer" />
</androidx.drawerlayout.widget.DrawerLayout>

我将感谢你的帮助，因为这真的很令人沮丧。如果需要更多信息，我会上传。

Answer 1

我认为您应该声明：

NavigationView leftNavigationView;

在您的主要活动中，并在创建方法上获得导航视图：

leftNavigationView = findViewById(R.id.nav_view);
setLeftNavigationView();

然后您必须使用setNavigationItemSelectedListener。你可以创建这样的方法：

private void setLeftNavigationView() {
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this,
drawerLayout,
toolbar,
R.string.navigation_drawer_open,
R.string.navigation_drawer_close);
drawerLayout.addDrawerListener(toggle);
toggle.syncState();
leftNavigationView.setNavigationItemSelectedListener(item -> {
Fragment selectedFragment = null;
switch (item.getItemId()) {
case R.id.nav_yourFragment:
selectedFragment = new YourFragment();
drawerLayout.closeDrawer(GravityCompat.START);
break;
}
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragment_container, selectedFragment).addToBackStack("tag")
.commit();
return true;
});

等等。R.id.nav_yourFragment是菜单中的项目此外，您还必须在xml文件中放入FrameLayout容器：

<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />

我希望这对你有用